The technical field of this invention relates to tissue engineered heart valves. Heart valve replacements are limited because donor tissues is in short supply. There are several types of valves that have been used for heart transplantations such as mechanical heart valves and bioprosthetic valves. The bioprosthetic valves are typically those obtained from other species and are known as xenografts. Porcine valves are the most common xenograft.
Unlike mechanical heart valves, bioprosthetics have a natural trileaflet structure and should have similar flow characteristics as human valves. However, in order to prevent immune responses to the cellular components of the valve, xenograft tissues are treated with chemical cross-linking agents such as glutaraldehyde. While this approach is successful in limiting acute rejection of these grafts, there are serious limitations. For example, leaflet flexibility is compromised, with the bending stiffness of the leaflets being significantly increased. Also, glutaraldehyde fixation increases the incidence and extent of leaflet and aortic conduit calcification. These factors combine to make bioprosthetic valves less durable and more prone to failure than natural valves.
Another major problem with replacement heart valves generally is the formation of blood clots and the risk of thrombosis. Thrombosis alters the mechanical fluid flow property of the valves and reduces their functionality as well as increasing the risk of heart failure in the patient.
Accordingly, a need exists for improved replacement heart valves that have a similar functionality as native heart valves but without the adverse effects of existing heart valves.